An exhaust gas recirculation (EGR) cooler according to the related art includes an EGR cooler cooling EGR gas, an EGR valve adjusting recirculation timing and an amount of the EGR gas, an EGR pipe connecting an intake manifold or an exhaust manifold and the EGR valve to each other, a cooling hose moving the coolant to the EGR cooler, and the like.
A coolant circulation circuit in the EGR cooler system according to the related art will be described below with reference to FIGS. 1 and 2. The coolant circulation circuit for cooling exhaust gas introduced into an EGR cooler 3 generally includes a water temperature controller (WTC) 2 into which a coolant exhausted from an engine 1 is introduced, the EGR cooler 3 and a heater 4 to which the coolant exhausted from the engine 1 is distributed through the WTC 2, and a water pump 5 receiving the coolant transferred from the EGR cooler 3 and the heater 4 and again introducing the coolant into the engine 1.
As illustrated in FIG. 2, the EGR cooler 3 according to the related art includes an inlet tank 7 positioned at a front end of the EGR cooler 3 and having exhaust gas introduced thereinto and distributed to a cooling core 8, the cooling core 8 configured of a plurality of linear tubes and having the introduced exhaust gas contacting an inner side thereof and a coolant contacting an outer side thereof to generate heat exchange, a body 9 having a structure in which it encloses the plurality of linear tubes configuring the cooling core 8 and inducing a flow of the coolant at an outer side of the plurality of linear tubes, a nipple 10 introducing the coolant from the outside into the body 9 or exhausting the coolant from the body 9 to the outside, and an outlet tank 11 exhausting the exhaust gas cooled through the cooling core 9 to the outside.
However, the EGR cooler according to the related art has a limitation in cooling efficiency since a flow rate of coolant supplied to the EGR cooler is equal to or smaller than a flow rate of coolant supplied to the heater.
In addition, the EGR cooler and the water temperature controller according to the related art should be repeatedly provided with the same components such as the nipples, the outlet tanks, and the like, in order to introduce and exhaust the coolant.
In addition, the EGR cooler according to the related art has been required to secure a space in which associated components are to be separately mounted. Therefore, the EGR cooler according to the related art had a difficulty in a layout design.